European patent application EP 1 640 055 A1 discloses a filter arrangement of the above-mentioned type. The filter element is accommodated in a filter housing consisting of a top part and a bottom part. Here, the filter element separates an unfiltered-air side from a filtered-air side. In this filter arrangement, insertable lamellae extend into the fold valleys of adjacent folds of the filter element. The extension of the insertable lamellae into the fold valleys is supposed to achieve a very low rate of air leakage between the unfiltered-air side and the filtered-air side.
A disadvantage of this sealing concept is that the length of the insertable lamellae has to be coordinated very precisely with the depth of the fold valleys in order to establish close contact of the insertable lamellae with the filter element.